The invention concerns a bicycle wheel having a metal rim and a hub which are connected together by means of a plastic spoke body, wherein the spoke body is an injection molded spoke body having a central portion which is connected to the hub and spokes which project in one piece radially from the central portion and whose distal ends are connected to the metal rim which has a hollow-chambered rim with an external flange and an internal flange, wherein a peripherally extending hollow rim chamber is determined by the external and internal flanges.
DE 199 21 578 A1 discloses a bicycle wheel in which the distal ends of the spokes are connected to the metal rim by means of anchoring elements. The anchoring elements extend through holes in the metal rim. The operation of mounting the anchoring elements to the metal rim requires a given amount of expenditure and complication in terms of manipulation and production.
A bicycle wheel of the kind set forth in the opening part of this specification is known from WO 95/04666 A1. There, the distal ends of the spokes are formed in one piece with the hollow-chambered rim. The hollow-chambered rim extends around the wheel. A metal rim is fixed to the hollow-chambered rim. The metal rim is in the form of a rim which is simply profiled in a U-shape. Suitable fixing means are provided there for fixing the metal rim which is of a U-shape profile to the hollow-chambered rim which is in one piece with the distal ends of the spokes. The fixing means are for example ribs and grooves or the like which are adapted in shape thereto.
DE 38 33 749 A1 discloses a pneumatic-tire vehicle wheel having a rim produced from sheet metal and with radially extending rim flanges and bead seat surfaces arranged therebeside at the periphery for the bases of a tubeless tire, and a cast wheel dish which is connected to the rim in the region of the rim well. The well of the rim is enclosed, with a rim in one or two parts, in the form of a drop-base or flat-base or raised-base rim, by an axially extending prolongation portion of the wheel dish.
DE 44 44 044 A1 discloses a rim wheel for bicycles or the like, in particular with a hollow-chambered rim with braking surfaces for a rim brake, the braking surfaces being formed by the oppositely disposed annular sides of the rim. In the case of that known rim wheel the rim profile is provided with slots or holes which are open towards the braking surfaces and which are arranged distributedly over the annular sides of the rim. In its region which is displaced towards the hub of the wheel with respect to the profile openings, the rim can be provided with through openings which are in indirect or direct communication with the profile openings, by way of the internal space of the profile, for a through-flow of air. The through openings are desirably provided at the annular inward side of the rim in order to be able to fix wheel spokes.
U.S. Pat. No. 5,707,114 discloses a bicycle wheel which can have a hollow-chambered rim connected to spokes by means of anchoring elements. Assembly of the hollow-chambered rim to the spokes there represents an amount of work which cannot be disregarded.
The object of the present invention is so to develop the bicycle wheel of the kind set forth in the opening part of this specification that the connection of the spoke body, that is to say the distal ends of the spokes, to the metal rim, does not require any specific assembly or production expenditure, while the requirement of material for that connection is relatively slight.
In the bicycle wheel of the kind set forth in the opening part of this specification, that object is attained in accordance with the invention in that the metal rim has a central flange which transversely subdivides the hollow rim chamber and which establishes a peripherally extending anchoring chamber adjoining the external flange, and that the external flange is provided with holes, wherein the distal ends of the spokes are integrally connected through the holes in the external flange to a peripherally extending spoke anchoring body comprising the material of the spoke body, wherein the spoke anchoring body completely fills the anchoring chamber delimited by the central flange.
The bicycle wheel according to the invention has the advantage that, in the operation of injection molding the spoke body, the injection molding material penetrates through the holes in the external flange of the hollow-chambered rim into the anchoring chamber which is provided in the hollow rim chamber and which is delimited by the central flange, and there forms a spoke anchoring body. Independent anchoring elements for fixedly connecting the distal ends of the spokes to the metal rim are therefore advantageously dispensable.
As the peripherally extending anchoring chamber which is delimited by the central flange can be relatively small in relationship to the remaining hollow rim chamber, that affords the advantage in accordance with the invention that the total weight of the bicycle wheel is only imperceptibly increased by the spoke anchoring body.
In the case of a bicycle wheel with a hollow-chambered rim with a central flange, it is also possible for the distal ends of the spokes of the injection molded spoke body to be connected to the metal rim by means of anchoring elements such as screw pins or the like because then both the external flange and also the central flange are available for fixing purposes, that is to say for screwing through the anchoring elements.
In the bicycle wheel according to the invention the distal ends of the spokes can be provided separately from each other and the external flange of the hollow-chambered rim can be provided with a number of holes, which corresponds to the number of spokes. Such a configuration of the bicycle wheel according to the invention has a relatively small number of spokes, for example three, four, five or six spokes. In accordance with the invention, another possibility provides that the distal ends of the spokes are integrally connected to a rim ring which is provided at the outside of the metal rim and which comprises the material of the spoke body. With such a design configuration of the last-mentioned kind, the number of holes in the external flange of the hollow-chambered rim is so-to-speak independent of the number of spokes because the rim ring extends around the external flange of the hollow-chambered rim. With such a configuration of the last-mentioned kind however it is preferable if the external flange of the hollow-chambered rim is provided with a number of holes, which corresponds to the number of spokes, in order to achieve optimum mechanical properties. In the case of a bicycle wheel of the last-mentioned kind the number of spokes can be relatively great. The same applies for the number of holes in the external flange of the hollow-chambered rim.